Condition-responsive monitor

ABSTRACT

A fluid pressure responsive device having two magnets with like poles facing each other. A first magnet is mounted with a piston to be movable in response to fluid pressure toward the other magnet to thus cause the other magnet to move due to repelling forces of the adjacent magnetic poles. A fixed armature, which may be adjustable, is located in the field of influence of said poles to control the repelling force which occurs between the magnets. The second magnet may used to actuate an indicating device.

United States Patent l3,6ll,220

[72] lnventor Leslie J. Hoffman 821 Derby-Milford Road, Orange, Conn.06477 [2]] Appl. No. 56,592 [22] Filed July 20, 1970 [45] Patented Oct.5, 1971 [54] CONDITION-RESPONSIVE MONITOR 12 Claims, 12 Drawing Figs.

[52] US. Cl 335/207, 200/82 R, 200/82 C [51] lnt.Cl H01h 5/02, HOlh35/38 [50] Field of Search 335/205, 207; 200/84 C, 81.9 M, 81.9 R, 82 R,82 C [56] References Cited UNITED STATES PATENTS 3,077,854 2/l963 Pall200/82 (C) X 3,293,579 12/1966 Harper OTHER REFERENCES Interlock Switch;Keller, et al.; IBM Technical Disclosure Bulletin; Vol. 10, No. l2, May1968, page 1926, copy in 335- 207.

Primary ExaminerBernard A. Gilheany Assistant Examiner-R. N. Envall,.lr.

CONDITION-RESPONSIVE MONITOR BACKGROUND This invention relates tosignalling or monitor devices, and more particularly tocondition-responsive or fluid pressure responsive devices which employmagnetic members to effect a signal or control.

Several prior signal or indicator devices intended to respond to changesin fluid or liquid pressure utilized cylinder-andpiston arrangementswherein the piston shifted as changes in fluid pressure occurred onopposite sides of a filter. The piston was connected with a permanentmagnet, or alternatively it was connected with a magnetic armature. Ineither case, an indicator device was provided in the form of a permanentmagnet which was cooperable with the magnet or armature controlled bythe piston. A strong attractive force existed which maintained theindicator device in a nonindicating condition, but if the piston and itsmagnet or armature was shifted away from the signal magnet, the latterbeing free for movement under the action of a biasing spring, shifted toa different position whereby it constituted an indication of theoccurrence of a significant pressure change.

Other indicator or signal devices have members which experience agradual change, these members being mounted directly on a piston whichwas shifted in response to changes in the fluid pressure. Thesegradual-movement-type indicators did not give as definite or distinct asignal as those in which an abrupt or snap action of the indicatormember occurred, when considering a clogged condition of the filterelement.

In other prior devices a pressure-actuated piston having a permanentmagnet was associated with a magnetic follower which gradually shiftedits position and which constituted the indication as to the differencein pressures caused by clogging of the filter. In still other devices amagnetic follower, which responded to a magnet carried by a float, wasemployed as a liquid level indicator, in connection with liquidcontaining vessels. I

While these various prior devices have in general operated more or lesssatisfactorily, they all had the common drawback or limitation that themode of operation was fixed and could not be altered to suit differentrequirements of the user. For example, those indicators which employed asnap action could not be readily changed to provide agradual or analogtype of indication, and the indicators which provided a gradual oranalog type indication could not be readily converted to provide a snapor definite on-off" type function. Moreover, the prior devices were inmany instances relatively large and complicated, having a great manyparts. In some cases the action of the parts was such that binding ormalfunctioning could occur, resulting in the device becominginoperative.

SUMMARY The above drawbacks and disadvantages of priorconditionresponsive monitors or controls are obviated by the presentinvention, which has for one object the provision of a novel andimproved condition or fluid-pressure responsive monitor which is capableof either a snap action or else a gradual action of the indicatormember, these constituting either a distinct on-off type response orelse an analog or gradual type response, the arrangement being such thatthe device is easily and quickly converted from one to the other type ofoperation at the will of the user. This is accomplished by a piston andcylinder arrangement wherein the piston carries a small permanent magnetmovable along a predetermined path of travel, and wherein there is anadjoining path of travel of a second or slave-type permanent magnetarranged to present a like pole to the nearest pole of thepiston-carried magnet. As a consequence, magnetic repulsion existsbetween the magnets, tending to separate the same. Adjacent the normal,nonindicating position of the second or slave magnet is a fixed magneticarmature which is normally influenced or magnetized by the slave magnetwhereby it tends to hold the latter in its nonindicating position. Whenthe piston-carried magnet is made to approach the armature and slavemagnet, it gradually overcomes the magnetic influence of the latter onthe fixed armature. Depending on the position of the armature, thechange or reversal in its magnetism as the piston-carried magnetapproaches, causes either a gradual shifting away of the slave magnet orelse a sudden snaplike shifting away of the latter. The magneticarmature is adjustably mounted whereby it can be interposed in the spacebetween the two magnets to effect the snap action of the slave magnet,or else removed somewhat from the space between the magnets wherebythere ensues a gradual, responsive movement of the slave magnet as thepiston-carried magnet is advanced on the latter. I

Other features and advantages of the inventionreside in the provision ofa novel and improved, convertible monitor which responds to changes in acondition as above set forth, wherein relatively few parts are involvedand wherein the construction is extremely simple, thereby reducing thefabricating cost; the provision of an improved convertible monitor ofthe kind indicated, which may be easily and quickly changed at the willof the user, from the gradual or analog type indication to the snapaction type; the provision of an improved conditionresponsive monitorwhich will readily actuate electrical switches such as microswitches,reed switches and the like to effect electrical controls, so as toilluminate a signal bulb for example; and the provision of an improvedmonitor as described above, wherein a reset type operation of theindicator may be readily had.

Still other features and advantages will hereinafter appear.

In the accompanying drawings illustrating several embodiments of theinvention:

FIG. 1 is a side elevational view of the improved convertiblecondition-responsive monitor or control device as provided by theinvention, shown without seals.

FIG. 2 is an axial sectional view taken on the line 2-2 of FIG. 1, butshowing seals.

FIG. 3 is a top plan view of the device of FIGS. 1 and 2.

FIG. 4 is a fragmentary axial sectional view illustrating a modifiedform of adjustable magnetic armature.

FIG. 5 is a view partly in top plan and partly in section, of themonitor device of FIG. 4.

FIG. 6 is a view partly in axial section of a reset type monitor deviceconstituting another embodiment of the invention.

FIG. 7 is a partial axial sectional view of a convertiblecondition-responsive control device having incorporated in it amicroswitch.

FIG. 8 is a partial axial sectional view of a convertiblecondition-responsive device in conjunction with reed switches, toactuate the latter.

FIG. 9 is a partial axial sectional view of a convertible deviceprovided with a signal or pilot light and cooperable switch contacts,for providing an electrical control or electrically operated signal.

FIG. 10 is a partial axial sectional view of a convertiblecondition-responsive device having pairs of switch contacts, which aremade operative and inoperative as the device responds to changingconditions.

FIG. 11 is a view partly in side elevation and partly in axial section,illustrating a flange-mounting type of housing for the device.

FIG. 12 is a side elevational view of a convertible monitor deviceincorporated in a line-mounting type of housing.

Referring first to FIGS. I-3, the present improved convertible monitordevice comprises a tubular housing 20 having a lower or cylinder portion22 in which there is reciprocatively carried a piston 24 having apacking or rubber O-ring 26. At the outer end of the cylinder 22 thereis provided a snap ring 28 constituting a stop for the piston, carriedin an annular internal groove 30 in the cylinder wall. Around itsexterior, the cylinder 22 has a packing or O-ring 32 adapted toconstitute a seal when the piston is inserted in a close-fitting bore ofa sup- ,porting fitting. The cylinder 22 has external screw threads 34by which it can be threaded into such fitting, and the housing has ahexagonal portion 36 adapted to accommodate a wrench, and also a packingor O-ring 38 to effect a seal with the mouth of the fitting into whichthe cylinder 22 is screwed.

Within the cylinder 22 there is a helical compression spring 40, engagedat one end with the adjoining end surface of the piston 24 and at itsother end with an annular spacer sleeve 42. As seen in FIG. 2, the boreof the cylinder 22 constitutes in effect a blind hole, in that thespacer sleeve 42 bottoms against a transverse wall 44 of the housing 20.

The cylinder 24 has a shank portion 46 to which there is affixed apermanent magnet 48 having north and south poles as indicated. In a wallof the cylinder 22 there is provided a port 49 whereby fluid pressurecan be brought to bear against the upper or inner end surface of thepiston 24, to counteract fluidpressure bearing against the bottom orouter end surface of the piston.

With such arrangement, pressure differential can be made to exist withrespect to the piston 24; when the pressure at the outer or bottom endof the piston increases it will overcome the biasing action of the coilspring 40, shifting the piston 24 upward in the cylinder and likewiseshifting upward the permanent magnet 48 which is herein termed a mastermagnet.

The housing 20 has a second bore 50 which is aligned with the bore ofthe cylinder 22 but has no communication therewith. A domelike orcup-shaped cover piece 52 of transparent material such as clear plasticis carried in the upper bore 50 of the housing 20 so as to enclose thebore, and a permanent slave magnet 54 is provided within the cover 52,to be readily movable therein between a nonindicating or lower positionas illustrated in FIG. 2 and an indicating or raised position wherein itoccupies the upper portion of the cover 52 and is clearly visible or inview.

In accordance with the present invention the slave magnet 54 has itsnorth pole lowermost, whereby it opposes the uppermost north pole of themaster magnet 48, thereby resulting in repulsion between the magnets 48and 54.

Also, disposed in the field of influence of the like north poles of themagnets 48, 54 and adjacent the paths of travel of the same there is astationary magnetic armature piece 56 in the form of a short length ofmagnetic or iron wire, said wire occupying a transverse bore 58 in thehousing 20 and being at one end carried by an adjusting screw 60 whichis threaded into the bore 58. As seen in FIG. 2, the magnetic armature56 is interposed in the space between the north poles of the magnets 48,54, and is located closely adjacent the latter (slave) magnet when itoccupies its lowermost or nonindicating position. The master magnet 48when in its lower position (indicating that a relatively low fluidpressure is being exerted at the bottom end of the piston 24) isrelatively remote from the armature 56.

With the parts in the positions illustrated in FIG. 2 the slave magnet54 dominates the magnetization of the armature piece 56, producing aflux therein which tends to oppose the flux from the north pole of themaster magnet 48, Movement of the master magnet 48 a given distanceupward toward the armature piece 56 will overcome the magnetic influencethereon by the slave magnet 54, eventually driving the latter away fromthe armature piece 56 and upward, into the upper portion of the coverpiece 52. Such upward movement of the slave or indicator magnet 54 willbe sudden, and will have a snap characteristic if the armature wire 56is interposed in the space between the two magnets as shown in FIG. 2.As presently understood, the magnetism of the north pole of the mastermagnet 48 as the magnet is driven upward by the piston 24 in respondingto pressure changes, will overcome the magnetic influence of the slavemagnet 54 on the armature piece. Such magnetic influence, prior toupward movement of the master magnet 42, has held the slave magnet 54 inits lower, nonindicating position. However, the upward movement of themaster magnet 48 in overcoming the magnetism in the armature piece 56 aseffected by the slave magnet 54 will, in effect, reverse such magnetismwhereby in place of the attractive force between the armature piece andthe slave magnet 54 there will now abruptly be a repulsive force,causing the slave magnet 52 to snap upward to a raised position in the Vcover piece 52. At such time that the piston 24 is caused to shiftdownward under the action of the spring 48 (due to removal of thedriving pressure from the bottom end of the piston 24) the magneticinfluence of the master magnet 48 on the armature piece 56 will becomeweakened, whereupon the weight of the slave magnet 54 and its magneticattraction for the armature piece 56 will be operative, resulting in theslave or indicator magnet 54 descending to the nonindicating position ofFIG. 2.

If the armature piece 56 is removed somewhat from between the northpoles of the magnets 48, 54, it will have a lesser effect in holding theslave magnet 54 against movement as the master magnet 48 is caused toshift upward due to pressure changes on the piston 24. In consequence,the upward gradual movement of the master magnet 48 will cause the slavemagnet 54 to shift upward gradually due to the repulsive forces existingbetween the magnets, such repulsive forces being altered or effected toa much lesser extent by the partially withdrawn armature piece 56.Accordingly, instead of a snap action movement of the slave magnet 54there will be a gradual or analog type movement of such slave magnet.

It will be seen that the type of response or movement of the slavemagnet 54 can be easily converted by the user, in a simple manner, bymerely turning the adjusting screw 60 inward or outward, to locate thearmature piece 56 either closer to or further from the space between thenorth poles of the opposing magnets 48, 54.

Another embodiment of the invention is illustrated in FIGS. 4 and 5. Inthis embodiment, components which are similar to those already describedhave been given like numerals. In the embodiments of FIGS. 4 and 5, inplace of the axially or longitudinally movable armature wire 56 there isprovided a flat metal armature strip of magnetic material, which ispivotally movable into and out of the sphere of influence of thepermanent magnets. As shown, the housing 20a has a horizontal slot orcut 62 in which there is disposed a flat strip of sheet metal 64constituting a magnetic armature piece. The strip 64 has a pivot holethrough which there extends a pivot screw 66 threaded into the housing20a. The exterior end of the armature piece 64 has knurling orserrations 68 constituting a finger grip, by which the strip may bereadily shifted from its fully operative, full line position illustratedin FIG. 5 to a relatively inoperative broken line position indicated at70 in FIG. 5. For the full line position of the armature piece 64 a snapaction of the slave magnet 54 will occur, whereas for the inoperativeposition of the armature piece 64 indicated at 70 in FIG. 5 a gradual oranalog type movement of the slave magnet 54 will be had.

Another embodiment of the invention is illustrated in FIG. 6, whereinlike components already described have been given similar characters. InFIG. 6, a cover piece 52b is provided in the bore 50 of the housing 20,said cover piece having a central opening in its top wall 53b, throughwhich there extends a stud 72 attached to an movable with the slavemagnet 54b. When the magnet 54b moves upward in the cover piece 52b, thestud 72 will protrude from the top of the cover piece. Against theunderside of the top wall 53b of the cover piece there is attached amagnetic keeper 74 in the form of a steel annulus. As the slave magnet54b moves upward to its raised indicating position, the south polethereof will attract the keeper 74 which is affixed to the cover piece521:. Accordingly, the slave magnet 54b will be retained in its raisedindicating position after having been shifted thereto in response toraising movement of the master magnet 48. This arrangement constitutes amanual reset, since it will be necessary for the user to depress thestud 72 so as to reset the slave magnet 54 to its lower, nonindicatingposition upon normal conditions being restored for the piston 24 andmaster magnet 48.

Yet another embodiment of the invention is illustrated in FIG. 7,wherein the monitor device constitutes a control. Mounted on the casing20c is a microswitch 76 having an actuator arm 78 which is disposed inthe path of travel of the slave magnet 54. At the time that the slavemagnet 54 is shifted to it raised position, it will actuate the arm 78of the micro switch 76, causing an actuation of the switch. The slavemagnet 54 is shiftable in a vertical tubular guide 80 carried by thehousing of the microswitch 76.

Yet another embodiment of the invention is illustrated in FIG. 8,wherein the housing 20d of the convertible monitorcontrol device carriesan enclosure 82 provided with an electrical connector fitting 84. Withinthe enclosure 82 are reed switches 86 having their lead wires connectedto the connector fitting 84. The reed switches 86 have magnetic elements88 which are influenced by the slave magnet 54. When the slave magnet isshifted to its raised position, it will actuate the magnetic elements 88from the reed switches 86, either closing or opening the same as thecase may be.

Still another embodiment of the invention is illustrated in FIG. 9,wherein the casing 20e is provided with an enclosure 90 on which thereis mounted a pilot light 92. An electrical circuit 94 including abattery 96 is provided for the pilot light, and included in such circuitare electrical contacts 98 carried by a circuit board 100. The contacts98 are engageable by the upper silvered surface 102 of the slave magnet54c. When the magnet 54c is shifted to a raised position, the silveredend surface l02 thereof will bridge the contacts 98, closing the circuitthrough the lamp 92 and effecting its energization, thereby indicatingthat the device has responded to a change in the conditions affectingit.

Yet another embodiment of the invention is illustrated in FIG. 10,wherein a casing 20f has an enclosure 104 carrying a connector fitting106. Within the enclosure 104, circuit boards 108 and 110 carry pairs ofelectrical contacts 112, 1 14 respectively which are engageablerespectively with the opposite silvered ends of a slave magnet 54f. Withthe slave magnet 54] in the lower position illustrated in FIG. 10, thecontacts 114 are bridged, whereas with the slave magnet in a raisedposition, the contacts 114 are not bridged but instead the contacts 112are bridged, thereby effecting a circuit control for signalling or otherequipment.

FIG. 11 indicates a flange mounting type housing 20g provided with anannular mounting flange 116 in place of the screw thread mounting 34illustrated in FIGS. 1 and 2.

In FIG. 12, a housing 20h is illustrated, having a tubular fittingportion 118 provided with internal end threads 120, 122 to receive pipefittings. A port 124 connects with one end portion of the fittingsection 118.

It will now be understood from the foregoing that I have provided anovel and improved, readily convertible conditionresponsive monitor orcontrol device which is especially simple in construction, involvingrelatively few parts which may be economically fabricated and assembled.The monitor may be quickly converted from either a snap, on-off type ofoperation to a gradual or analog type operation, by merely shifting amagnetic armature piece between its operative and inoperative positions.The device is effective and reliable in use, not subject to leakage ormalfunctioning, and is readily adaptable to monitor a variety ofdifferent conditions wherein changes occur.

Variations and modifications are possible without departing from thespirit of the invention.

lclaim:

1. A condition-responsive monitor comprising, in combination:

a. a permanent master magnet,

b. means mounting the master magnet for movement in either of oppositedirections along a predetermined path of travel,

c. a drive device responsive to changes in a condition, for

shifting said permanent magnet in said path,

d. a permanent slave magnet,

e. means mounting the slave magnet for movement in either of oppositedirections along a predetermined path of travel adjoining andnoncoincidental with said first-mentioned path of travel,

f. said magnets being arranged with a pair of like poles directed towardeach other, thereby causing opposing forces to exist between themagnets, which tend to separate the same,

g. a stationary magnetic armature piece disposed in the field ofinfluence of said like poles of the magnets, adjacent the paths oftravel of the same,

h. means biasing said master magnet to a position away from saidarmature piece whereby it is movable toward the piece and against saidbiasing means in response to changes in said condition,

. said slave magnet being normally close to the armature piece,dominating the magnetization thereof, and producing a flux thereinaccording to a given polarity, movement of the master magnet a givendistance toward the armature piece overcoming the magnetic influencethereon by the slave magnet and driving the latter away from thearmature piece to a position relatively remote therefrom.

2. A condition-responsive monitor as in claim 1, wherein:

a. said armature piece is disposed between said like poles of themagnets,

b. said slave magnet being driven away from the armature piece with asnap action when the master magnet overcomes the slave magnetization ofsaid piece as it moves toward the latter.

3. A condition-responsive monitor as in claim 1, wherein:

a. said armature piece is disposed adjacent the space between said likepoles of the magnets,

b. said slave magnet shifting slowly away from the armature piece whenthe master magnet overcomes the slave magnetization of said piece as itslowly moves toward the latter.

4. A condition-responsive monitor as in claim 1, wherein:

a. said drive device comprises a piston and cylinder,

b. said master magnet being connected to said piston to be shiftedthereby,

c. said cylinder. having passages at opposite ends of the piston toadmit pressurized fluid.

5. A condition-responsive monitor as in claim I, wherein:

a. said armature piece comprises a magnetic wire, and

b. means for adjustably positioning said wire, said means comprising ascrew carrying said wire in alignment with its axis whereby turning ofthe screw either advances the wire into the space between said likemagnet poles or retracts the wire from said space.

6. A condition-responsive monitor as in claim 1, wherein:

a. said armature piece comprises a strip of magnetic sheet metal, and

b. means for adjustably positioning said strip, said means comprisingpivot means for enabling the strip to be swung into or out of the spacebetween said like magnet poles.

7. A condition-responsive monitor as in claim 1, and further including:

a. a magnetic keeper disposed in the path of travel of the slave magnet,for yieldably holding the latter in shifted position as effected by themaster magnet.

8. A condition-responsive monitor as in claim I, and further including:

a. a microswitch, and

b. means for actuating said switch in response to shifting of the slavemagnet by said master magnet.

9. A condition-responsive monitor as in claim I, and further including:

a. a reed switch having a magnetic actuator member,

b. said reed switch being disposed in the field of influence of theslave magnet to be actuated thereby when the magnet is shifted by themaster magnet.

10. A condition-responsive monitor as in claim 1, and

further including:

a. a pilot light,

12. A condition-responsive monitor as in claim 4, and further including:

a. a tubular housing comprising said cylinder, b. said master and slavemagnets being axially shiftable in the bore of the housing, c. saidbiasing means comprising a coil spring in the housing bore andencircling the master magnet.

1. A condition-responsive monitor comprising, in combination: a. apermanent master magnet, b. means mounting the master magnet formovement in either of opposite directions along a predetermined path oftravel, c. a drive device responsive to changes in a condition, forshifting said permanent magnet in said path, d. a permanent slavemagnet, e. means mounting the slave magnet for movement in either ofopposite directions along a predetermined path of travel adjoining andnoncoincidental with said first-mentioned path of travel, f. saidmagnets being arranged with a pair of like poles directed toward eachother, thereby causing opposing forces to exist between the magnets,which tend to separate the same, g. a stationary magnetic armature piecedisposed in the field of influence of said like poles of the magnets,adjacent the paths of travel of the same, h. means biasing said mastermagnet to a position away from said armature piece whereby it is movabletoward the piece and against said biasing means in response to changesin said condition, i. said slave magnet being normally close to thearmature piece, dominating the magnetization thereof, and producing aflux therein according to a given polarity, movement of the mastermagnet a given distance toward the armature piece overcoming themagnetic influence thereon by the slave magnet and driving the latteraway from the armature piece to a position relatively remote therefrom.2. A condition-responsive monitor as in claim 1, wherein: a. saidarmature piece is disposed between said like poles of the magnets, b.said slave magnet being driven away from the armature piece with a snapaction when the master magnet overcomes the slave magnetization of saidpiece as it moves toward the latter.
 3. A condition-responsive monitoras in claim 1, wherein: a. said armature piece is disposed adjacent thespace between said like poles of the magnets, b. said slave magnetshifting slowly away from the armature piece when the master magnetovercomes the slave magnetization of said piece as it slowly movestoward the latter.
 4. A condition-responsive monitor as in claim 1,wherein: a. said drive device comprises a piston and cylinder, b. saidmaster magnet being connected to said piston to be shifted thereby, c.said cylinder having passages at opposite ends of the piston to admitpressurized fluid.
 5. A condition-responsive monitor as in claim 1,wherein: a. said armature piece comprises a magnetic wire, and b. meansfor adjustably posItioning said wire, said means comprising a screwcarrying said wire in alignment with its axis whereby turning of thescrew either advances the wire into the space between said like magnetpoles or retracts the wire from said space.
 6. A condition-responsivemonitor as in claim 1, wherein: a. said armature piece comprises a stripof magnetic sheet metal, and b. means for adjustably positioning saidstrip, said means comprising pivot means for enabling the strip to beswung into or out of the space between said like magnet poles.
 7. Acondition-responsive monitor as in claim 1, and further including: a. amagnetic keeper disposed in the path of travel of the slave magnet, foryieldably holding the latter in shifted position as effected by themaster magnet.
 8. A condition-responsive monitor as in claim 1, andfurther including: a. a microswitch, and b. means for actuating saidswitch in response to shifting of the slave magnet by said mastermagnet.
 9. A condition-responsive monitor as in claim 1, and furtherincluding: a. a reed switch having a magnetic actuator member, b. saidreed switch being disposed in the field of influence of the slave magnetto be actuated thereby when the magnet is shifted by the master magnet.10. A condition-responsive monitor as in claim 1, and further including:a. a pilot light, b. an energizing circuit for the pilot light, and c.cooperable contacts controlling said energizing circuit and actuated bysaid slave magnet when the latter is shifted by said master magnet. 11.A condition-responsive monitor as in claim 1, and further including: a.pairs of electrical contacts respectively bridged by the slave magnetwhen the latter is either close to said armature piece or else shiftedaway therefrom.
 12. A condition-responsive monitor as in claim 4, andfurther including: a. a tubular housing comprising said cylinder, b.said master and slave magnets being axially shiftable in the bore of thehousing, c. said biasing means comprising a coil spring in the housingbore and encircling the master magnet.